Russo-Turkish wars,series of wars between Russia and the Ottoman Empire in the 17th–19th century. The wars reflected the decline of the Ottoman Empire and resulted in the gradual southward extension of Russia’s frontier and influence into Ottoman territory. The wars took place in 1676–81, 1687, 1689, 1695–96, 1710–12 (part of the Great Northern War), 1735–39, 1768–74, 1787–91, 1806–12, 1828–29, 1853–56 (part of the Crimean War), and 1877–78. As a result of these wars, Russia was able to extend its European frontiers southward to the Black Sea, southwestward to the Prut River, and south of the Caucasus Mountains in Asia.

The early Russo-Turkish Wars were mostly sparked by Russia’s attempts to establish a warm-water port on the Black Sea, which lay in Turkish hands. The first war (1676–81) was fought without success in Ukraine west of the Dnieper River by Russia, which renewed the war with failed invasions of the Crimea in 1687 and 1689. In the war of 1695–96, the Russian tsar Peter I the Great’s forces succeeded in capturing the fortress of Azov. In 1710 Turkey entered the Northern War against Russia, and after Peter the Great’s attempt to liberate the Balkans from Ottoman rule ended in defeat at the Prut River (1711), he was forced to return Azov to Turkey. War again broke out in 1735, with Russia and Austria in alliance against Turkey. The Russians successfully invaded Turkish-held Moldavia, but their Austrian allies were defeated in the field, and as a result the Russians obtained almost nothing in the Treaty of Belgrade (Sept. September 18, 1739).

The first major Russo-Turkish War (1768–74) began after Turkey demanded that Russia’s ruler, Catherine II the Great, abstain from interfering in Poland’s internal affairs. The Russians went on to win impressive victories over the Turks. They captured Azov, the Crimea, and Bessarabia, and under Field Marshal P.A. Rumyantsev they overran Moldavia and also defeated the Turks in Bulgaria. The Turks were compelled to seek peace, which was concluded in the Treaty of Küçük Kaynarca (July 21, 1774). This treaty made the Crimean khanate independent of the Turkish sultan; advanced the Russian frontier southward to the Southern (Pivdennyy) Buh River; gave Russia the right to maintain a fleet on the Black Sea; and assigned Russia vague rights of protection over the Ottoman sultan’s Christian subjects throughout the Balkans.

Russia was now in a much stronger position to expand, and in 1783 Catherine annexed the Crimean Peninsula outright. War broke out in 1787, with Austria again on the side of Russia (until 1791). Under General A.V. Suvorov, the Russians won several victories that gave them control of the lower Dniester and Danube rivers, and further Russian successes compelled the Turks to sign the Treaty of Jassy (Iaşi) on Jan. January 9, 1792. By this treaty Turkey ceded the entire western Ukrainian Black Sea coast (from the Kerch Strait westward to the mouth of the Dniester) to Russia.

When Turkey deposed the Russophile governors of Moldavia and Walachia in 1806, war broke out again, though in a desultory fashion, since Russia was reluctant to concentrate large forces against Turkey while its relations with Napoleonic France were so uncertain. But in 1811, with the prospect of a Franco-Russian war in sight, Russia sought a quick decision on its southern frontier. The Russian field marshal M.I. Kutuzov’s victorious campaign of 1811–12 forced the Turks to cede Bessarabia to Russia by the Treaty of Bucharest (May 28, 1812).

Russia had by now secured the entire northern coast of the Black Sea. Its subsequent wars with Turkey were fought to gain influence in the Ottoman Balkans, win control of the Dardanelles and Bosporus straits, and expand into the Caucasus. The Greeks’ struggle for independence sparked the Russo-Turkish War of 1828–29, in which Russian forces advanced into Bulgaria, the Caucasus, and northeastern Anatolia itself before the Turks sued for peace. The resulting Treaty of Edirne (Sept. September 14, 1829) gave Russia most of the eastern shore of the Black Sea, and Turkey recognized Russian sovereignty over Georgia and parts of present-day Armenia.

The war of 1853–56, known as the Crimean War(q.v.), began after the Russian emperor Nicholas I tried to obtain further concessions from Turkey. Great Britain and France entered the conflict on Turkey’s side in 1854, however, and the Treaty of Paris (March 30, 1856) that ended the war was a serious diplomatic setback for Russia, though involving few territorial concessions.

The last Russo-Turkish War (1877–78) was also the most important one. In 1877 Russia and its ally Serbia came to the aid of Bosnia and Herzegovina and Bulgaria in their rebellions against Turkish rule. The Russians attacked through Bulgaria, and after successfully concluding the Siege of Pleven they advanced into Thrace, taking Adrianople (now Edirne, Tur.) in January 1878. In March of that year Russia concluded the Treaty of San Stefano with Turkey. This treaty freed Romania, Serbia, and Montenegro from Turkish rule, gave autonomy to Bosnia and Herzegovina, and created a huge autonomous Bulgaria under Russian protection. Britain and Austria-Hungary, alarmed by the Russian gains contained in the treaty, compelled Russia to accept the Treaty of Berlin (July 1878), whereby Russia’s military-political gains from the war were severely restricted.